Diabetes mellitus (DM) is caused by the deficiency of insulin production that functions in the utilization of glucose as the source of energy and fat synthesis so that the lack of insulin hormone will increases the blood glucose level. Traditionally, sweet potato leaves have been used for the treatment of diabetes, cancer, as antioxidant, hyperlipidemic, by natives in different regions and also to cure dengue fever.
The objectives of this study were to analyze antidiabetic activity of n-hexane extract (NHE), ethylacetate extract (EAE), and ethanol extract (EE) of SPLs in streptozotocin-induced mice and to determine the extract of the highest activity. This study consisted of plant material procurement and extract preparation, phytochemical screening, mice blood glucose level examination, and data analysis. The experimental animals (n=25) were divided into 5 groups: control group treated with 0.5% carboxymethylcellulose (CMC) suspension, positive control group treated with metformin suspension with a dose of 65 mg/kg bw, three test groups NHE, EAE, and EE of SPLs. Analysis of their antidiabetic activity was started by measuring glucose tolerance to identify the extract of the highest activity at varied dosages ( 100, 200, and 300 mg/kg bw) of this extract was examined on the streptozotocin-induced mice. Anova and Duncan tests were performed to test the significance of of these extracts, effects.
This study showed that NHE contained: water 1.99%; total ash 1.26%; acid-insoluble ash 0.24%; ethanol-soluble extract 36.49%; water-soluble extract 2.05%. Ethyl acetate extract contained: water 7.98%; total ash 1.59%; acid-insoluble ash 0.43%; ethanol-soluble extract 31.4%; water-soluble extract 4.43%. Ethanol extract contained: water 9.96%; total ash 1.44%; acid-insoluble ash 0.32%; ethanol-soluble extract 11.2%; water-soluble extract 41.61%. Phytochemical screening demonstrated the presence of flavonoid, saponin, and tannin in EAE and EE of SPLs. The antidiabetic activity of extracts in deacreasing order laters their activity was EE, EAE, metformin, and NHE. Three-day treatment with EAE 200 mg/kg bw and 300 mg/kg bw gave the same effect as that of 65 mg/kg bw metformin. At the fifth day of treatment, all extracts at dosages showed exerted antidiabetic effect, except 0.5% CMC. At the fifteenth day of treatment, all extracts at dosages of 100, 200, and 300 mg/kg bw exerted similar effects to those of metformin, except 0.5% CMC. Antidiabetict effect exerted by EE of SPLs 300 mg/kg bw was significantly different from that produced by EAE 100 mg/kg bw (Duncan test; α = 0.05).